Iowa's bishops have asked Catholics to fast as a way to demonstrate their concerns over mandates in the federal health care law.
Siouxland parishioners have been asked to fast on March 30 to highlight what the bishops call "ongoing religious liberty concerns."
The bishops say in a letter that the law will force religious people and groups to violate their "most deeply held convictions."
The federal policy requires nearly all employers to provide insurance coverage that includes free birth control for workers.
Houses of worship are exempt; religiously affiliated charities, hospitals and schools are not.
Bishops and others consider the religious exemption too narrow. President Barack Obama has said insurance companies would pay for the coverage instead of religious employers.